If the owners of the copyright are concerned about the recent developments of the Mongoose line, Id say its a reasonable bet to assume that they lacked faith in the latest unreleased manuscripts. The copyright owners have a vested interest in not letting any substandard material see the light of day. Im not saying that the material IS substandard, but Id say that they consider this to be the case.
I wouldnt consider there to be any real possibility, either, that this material will ever be available, simply because it will not benefit the copyright holders in any way to allow its publication. And Mongoose cant afford the time to get it to a finished state, with the very real threat of it being rejected at the last moment, either for legitimate reasons or pure spite (unlikely though that may be).
Id say weve already seen the last of the Mongoose Conan material.